Matthews Brothers made a large number of props for the Navy. The company was managed by Tom Hamilton, who went on to Hamilton Standard fame. The "S.E." refers to "Steam Engineering", which was the Navy Department responsible for procuring propellers in the late teens and early twenties.

It's stamped "F 5 L", which almost certainly refers to the Felixstowe F5L flying boat designed in England but developed by the Navy in the U.S.